Technical Ducato 250 - All read lights fail! BCM?

[mcbcotje]

Hello,

Recently my Ducato is missing any lighting on the rear (front is all OK). The OBD-scan reports all B10xx codes for brake/indicator/light as 'Signal High'/'Fatal'. Clearing the code does work, but as soon as I use the lights or brake the codes reappear. Assumably I have a short somewhere, but I disconnected the rear lights at the end of the loom on the rear of the chassis, and still the same issue. Seems like I have a short in between or maybe a failed BCM.

Anyone familiar with this behavior?

To do some more testing I'm looking for a description of the connectors on the fuse-box/BCM and preferably also the pin-out. Any tips to look for this?

TIA!

 

[Communicator]

Hello,

Recently my Ducato is missing any lighting on the rear (front is all OK). The OBD-scan reports all B10xx codes for brake/indicator/light as 'Signal High'/'Fatal'. Clearing the code does work, but as soon as I use the lights or brake the codes reappear. Assumably I have a short somewhere, but I disconnected the rear lights at the end of the loom on the rear of the chassis, and still the same issue. Seems like I have a short in between or maybe a failed BCM.

Anyone familiar with this behavior?

To do some more testing I'm looking for a description of the connectors on the fuse-box/BCM and preferably also the pin-out. Any tips to look for this?

TIA!

I am wondering about the possibility of a missing earth connection, causing these symptoms.
For BCM connections x250 Training Manual in Downloads at top of page is helpful, and easy to download.

I do not like TIA, much prefer that you provide feedback to help others with similar problem.

 

[mcbcotje]

Thanks Communicator! And, I will of course provide feedback. Ducato is all new to me, but electronics should be no problem. I'm used to wiring and programming aftermarket ECU/PDM's.

For now I think the file "CONECTORES Y FUSIBLES DUCATO III" will help me troubleshoot further. I need to find the connector on the fuse/bcm box that drives the rear lightning. As you stated, I might have a common ground error here. The question now only is: where? I already checked and cleaned the ground on the rear of the chassis. Btw, this Ducato is equipped with a trailer-box (ECS 5d033), but I eliminated this being the issue by connecting the original connectors on the rear of the chassis.

The issue probably started after cleaning the cabin area and checking the steering column for the cruise-control connector (was not there). No modules, wires or connectors were taken off btw.

Will update as soon as I find something!

 

[mcbcotje]

Today I've been working on testing the rear-lights by using the ECS trailer-module (which is in-between the loom to the rear). I disconnected the ECS connectors and was able to successfully drive all lights on the trailer-connector using my bike hitch-mount. Same for the rear lights where I found one bulb was defective, LR-brake doesn't work and license plate light is not coming on with normal-beam. No shorts at least (I used a fused-lead). There is some troubleshooting to do but I think the wiring to the rear is OK.

Below the output of the Multiscan errors. After clearing them, the errors appear only if I trigger the function. This makes me believe the CAN-commands are arriving at the BCM and working just fine. That would mean the output stages of the BCM cannot drive these circuits. Still strange they are all grouped to REAR functions. Front is working just fine.

Any input/ideas would be appreciated!

 

[mcbcotje]

Hello all, after some extensive troubleshooting I have compiled a sheet that describes all connections from the BCM-loom through the ECS-box, ending at the rear lights. I now know at least how to power all lights on the rear (including the trailer functions). This also meas I do not have an issue/shorts with the loom or connectors and I'm coming to the conclusion the BCM is defective. Attached the wiring details for my X250 Ducato!